(1) Field of the Invention
The present invention relates to a process for producing cyclodextrins and, more particulary, to a process which comprises cultivating microorganisms belonging to genus Micrococcus capable of producing cyclodextrin glycosyltransferase (E.C. 2.4.1.19), treating starch or degraded starch with the enzyme obtained by said cultivation or a composition containing such enzme to provide cyclodextrins and, if desired, recovering cyclodextrins thus produced.
The cyclodextrins according to the present invention are crystalline dextrin, which are also called "Schardinger dextrin".
They are cyclic oligosaccharide composed of 6, 7 or 8 glucose residues which are bound by .alpha.-1,4-bonds. They are called .alpha.-, .beta.- or .gamma.-cyclodextrin depending on the number of carbon residue, 6, 7 or 8, respectively.
The cyclodextrin has been known as monomolecular host molecule which has torus in the molecule capable of including various kinds of organic compounds (guest compounds). This specific inclusion has been widely used in fields of medicine, agricultural chemicals, foods, cosmetics, perfumes and the like.
(2) Description of the Prior Art
The process for preparation of the cyclodextrins have already described by Tilden and Hudson (J. Am. Chem. Soc. 64, 1432 (1942) ) and D. French (J. Am. Chem. Soc. 71, 353 (1949) ), in which the cyclodextrins have been produced by treating starch with the enzyme from Bacillus macerans, the so-called "macerans amylase".
Recently Bacillus stearothermophilus (Proc. Symp. Amylases (Osaka) 18, 43 (1973) ) (Japan Kokai SHO 50-63189), Bacillus megaterium (Agr. Biol. Chem. 38, 387 (1974) ) (Japan Kokai SHO 48-40996), Bacillus circulans (Proc. Symp. Amylases (Osaka) 18, 21, (1973) ), Bacillus ohbensis sp. (Japan Patent Publication SHO 52-31949) and Bacillus sp. No. 38-2 (ATCC 21783) (Die Starke, 27, 410 (1975) ) have been known as a microorganism which produces a similar enzyme. All the microorganisms belong to genus Bacillus. As such strain belonging to genus other than Bacillus, only Klebsiella pneumoniae M5 (Arch. Microbiol. 111, 271 (1977) ) has been reported. But there has been no report on production of such enzyme by any microorganism except for the microorganisms belonging to genus Bacillus and Klebsiella pneumoniae M5.